Improvement in lifting-jacks



H. W. CRNELL.

Lifting-lacks.

N0..l52,6`08 Y Patented .lune 30,1874.

WITNESSES. INVENTUR Attorneys.

UNITED STATES.` PATENT QEFICE.

HARMON W. CORNELL, OF OVVEGO, NEW YORK.

IMPROVEMENT IN LIFTINGYJACKS.

Specification forming part of Letters Patent No. 152,608, dated June 30, 1874; application lled Masr 21, 1874.

To all 'whom it may concern:

Beit known that I, HARMON W. CORNELL, of Owego, in the county of Tioga and in the State of New York, have invented certain new and useful Improvements in Liftin g-Jack; and do hereby declare that the following is a full, clear, and exact description thereof, reference being had to the accompanying drawings, and to .the letters of reference marked thereon, making a part of this specification.

The nature of my invention consists in the construction and arrangement of a lifting-j ack, as will be hereinafter more fully set forth.

In order to enable vothers skilled in the art to which my invention appertains to make and use the same, I will now proceed to describe its construction and operation, referring to the annexed drawing, in which- Figure l is a side elevation of my liftingjaclr. Fig. 2 is a longitudinal section of the operating lever and pawls, with a part of the movable upright. Fig. 3 is a horizontal section through the line .r x, Fig. l. Figs. 4 and 5 are cross-sections of the handle through the lines g/ y and x m, respectively.

A represents the base or bed piece ot' my lifting-jack, upon which is firmly secured an upright standard. In a sin gle-lever jack this standard is constructed, as shown in Fig. 3, of two uprights, B B, with a back, B1, and two front cross-bars, I32 B2, firmly bolted thereto. In a double-lever jack the back B1 is omitted, and two cross-bars used on this side also. In

' this upright standard is placed the movable cured plates E E, which extend inward in front of the movable upright C close to the rack-bar a. On each of the plates E is a forward-projecting ange, E', said plate and iiangc, with braces b b, being all cast in one piece, as shown. G represents the operatinglever, on each side of which, at the inner end, is secured a cast plate, G'. These plates are each provided with a ange, d, on the upper edge, and a ange, d', on the lower edge, which flanges extend inward and t over the top and bottom of the lever G. The plates G G are pivoted between the anges E E by means of a single bolt, f, passing through them, and on this bolt, between the plates G, l

is pivoted a pawl, I, to engage in the rackbar a ot' the movable upright C. J represents another pawl, pivoted between the plates G G at a point a suitable distance inward from and below the pivot of the pawl I when the lever is in a horizontal position, as shown in Fig. 2.

When the lever G s worked up and down the pawl I retains the same relative position to the movable upright C and its rack-bar a, while the pawl J moves downward when the lever is raised, and upward when the lever is depressed; hence, when the lever is elevated, the pawl I will hold the lnovable upright steady in place, while the pawl J will move downward to take a new hold on the rack-bar, and when the lever is pressed down said pawl J will raise the movable upright and lift the article under which the jack is placed. g

For very heavy work two levers are usedone on each side-as shown by dotted lines in Fig. l, in which ease the baci; B1 of the stationary standard is omitted, as above mentioned, and the movable upright provided 'with another raelibar.

May, 1874.

H. w. CORNELL.

Titnesses A. N. MARR, U. L. EVERT. 

